How to Solve Blackened Spark Plugs?
3 Answers
The solution for blackened spark plugs is to clean them promptly or replace them directly. Steps for replacing spark plugs: Open the engine hood, lift the plastic cover of the engine, remove the high-voltage distributor wires, and mark the position of each cylinder to avoid confusion. Use a spark plug socket to remove the spark plugs one by one. While removing, check for any external debris like leaves or dust and ensure they are thoroughly cleaned. Place the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it further. Reinstall the removed high-voltage distributor wires according to the firing order, and then secure the cover. Spark plug replacement interval: Under normal maintenance conditions, replace them after driving 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type. It is recommended to follow the user manual. The following standards can be referenced for maintenance replacement: Platinum spark plugs should be replaced at 40,000 kilometers, ordinary nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs at 60,000 to 80,000 kilometers.
Last time my car's spark plugs also turned black. I found out the issue after driving my decade-old Ford Focus with severe engine shaking. The main cause is incomplete combustion, such as an overly rich air-fuel mixture or engine oil seeping into the cylinders. Fixing it isn't too difficult. I first tried cleaning the carbon deposits on the spark plug heads with a specialized cleaner and a toothbrush, which worked decently. But if they're too black, you'll have to replace them with new ones—just make sure to choose the correct model. I also recommend checking the air filter; if it's clogged, the engine won't get enough air, worsening the problem. The fuel injectors should also be cleaned of deposits. Additionally, don't overlook driving habits—short trips or aggressive acceleration can lead to carbon buildup. Like me, taking regular long drives can help burn off some carbon. After replacement, the engine runs much smoother, fuel consumption dropped by 5%, and maintenance costs are reasonable. It's best to check every 20,000 kilometers to prevent recurrence.
As a car enthusiast, I often tinker with spark plugs myself. Blackening is usually a sign of carbon buildup or fuel mixture imbalance, which could be caused by leaking fuel injectors or voltage issues. The solution is to first clean the spark plug electrodes with carburetor cleaner, and if that doesn't work, simply replace them with new ones; I prefer using iridium spark plugs for their high durability and resistance to oxidation. At the same time, I measure the ignition coil impedance to ensure normal output, as unstable current can also lead to incomplete combustion. Don't forget to check the oxygen sensor readings for auxiliary diagnosis—this tool can indicate whether the air-fuel ratio is off. Overall, timely maintenance can improve ignition efficiency and performance. For example, I inspect the engine bay every three weeks to keep the car in top condition, and clean spark plugs make for smoother acceleration.
